1. Field of the Invention
The present invention relates to a camera and a battery pack which is removably attached to a camera body of the camera.
2. Description of the Related Art
Conventionally, there has been provided a single-lens reflex camera with a high performance, which is intended to be manufactured particularly for a camera professional and/or an amateur with a high level of photographing skill or technique. In such a single-lens reflex camera, there is a possibility that an unexpected shortage of power supplied from a battery, accommodated in a battery chamber of the camera, may hinder the photographer, or the user, from taking a photograph with the camera. Therefore, in order to prevent such an inconvenience, a separate or independent accessory (i.e. battery pack), for example, which can house a battery having a greater capacity and which can be voluntarily attached to a camera body of the camera, has been conventionally employed. With this arrangement, a plurality of power source systems can be provided.
For instance, U.S. Pat. No. 4,697,909 discloses a camera in which a battery pack, attached to a bottom part of the camera body, houses two kinds of power sources one of which can be selected by a switching member.
On the other hand, Japanese Laid-Open Patent Publication No. 8-54671 discloses a camera in which a separate, or independent, power source pack (or a battery pack), able to be attached to the camera body, can house a plurality of kinds of power sources any one of which can be selected by a switching member.
According to the arrangement, however, an operation to reset the microcomputer inside the camera body, upon the switchover between the power source systems, is not considered at all. The microcomputer for controlling the operation of the camera is operated on the basis of the electric power supplied thereto, and the microcomputer stops its operation when the supply of the electric power from the power source stops. When the electric power is started to be fed to the microcomputer once after the power supply is cut, it is necessary to firstly reset the microcomputer, and then to actuate the microcomputer again. Namely, the microcomputer can not be actuated, or operated, from a state that the software has once been stopped due to the cut of the power supply. Unless the microcomputer is re-actuated, or re-operated, in such a manner, the camera does not operate properly and correctly. Or, unless the microcomputer is re-actuated, or re-operated, in such a manner, even though it seems that the camera operates properly or correctly, the camera may not actually operate properly or correctly.
As the resetting operation, there are two resetting methods. The first resetting method is a resetting method which is executed with respect to a software. In this first resetting method, the software is constructed so that a resetting sequence is performed when the electric supply from a power source is started to the microcomputer.
On the other hand, the second resetting method is a resetting method which is executed mechanically. In this second resetting method, a reset switch (or resetting switch) is mechanically turned on in unison with replacing batteries, or in unison with closing a lid of the battery chamber.
However, according to the first resetting method, the construction of a software becomes complicated because there is a need of linking with other softwares for controlling other operations/functions of the camera. Also, according to the first resetting method, the resetting operation may be unstable, depending upon a condition of the power source of the camera.
Meanwhile, according to the second resetting method, it is possible to reset the microcomputer precisely, independently of the software. However, there is a need of performing a mechanical interlocking operation. Therefore, it is not possible to reset the microcomputer, with a construction in which a power source is selected from a plurality of power sources, for example without replacing a battery with another.
By the way, each of the aforementioned U.S. Pat. No. 4,697,909 and Japanese Laid-Open Patent Publication No. 8-54671, does not disclose the resetting operation of the microcomputer.